Question

Helium is given in a temperature of 100 C. the average kinetic energy of helium is given by E=3/2*n*R*T.
calculate the de broglie wavelength of the average helium atom in this temperature.

if you can please write the whole calculation and not only the solution, tnx :)

Answer 1

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/debrog2.html#c2

Answer 2

hey aaron, first of all (I'm just guessing by the name) if you're an Israeli we can switch to hebrew.

secondly, I have all of the equations, I also have the final result. from some reason I'm not getting the same numbers that's why I asked for the way to solve it. if you can write it down that could be great .

Answer 3

*for some reason

Answer 4

not israeli, sorry. i mean it's just a question of plugging stuff in and solving, did you try it with both the relativistic and the non-?

Answer 5

I calculated the average kinetic energy of one helium atom by using this formula:
\[\epsilon= \frac{ 3 }{ 2 }*k_{b}*T\]
then using the energy I found the average speed of the helium atom using this formula:
\[E=\frac{ 1 }{ 2 }*m*V^{2}\]
and then to find the de broglie wavelength of the average helium atom I used this formula:
\[\lambda_{Db}=\frac{ h }{ p }=\frac{ h }{ m*v }\]
for m I took the Mw of helium from the periodic table and divided it by Na (avogadro constant).

Answer 6

\[\epsilon=7.7211\times 10^{-23}\]
\[m=6.6456\times 10^{-24}\]
v=48.2044
\[\lambda _{Db}=2.0665\times10^{-12}\]
the right answer is
\[\lambda _{Db}=65.5\times ^{-12}\]

Answer 7

I found out that I forgot change unites for the mass and that I used gr instead of Kg so the mass should be 6.6456*10^-21

Answer 8

but now the answer i get is 655e-12 instead of 65.5e-12

Answer 9

theres definitely an error in the unit conversions your answer is way too close to not be that.

Answer 10

k tnk you I'll keep on looking, it's good to know I'm on the right path :)

Answer 11

no prob, good luck!